St. Mary's Drivetrain Repair & Maintenance

CV Shafts & Boots

The constant velocity (CV) shaft, boot and joints are used on front wheel-drive and many four wheel-drive automobiles.

Maintenance and automobile:

CV boots should be inspected by a St. Mary's AAMCO mechanic with every oil change and are inspected as part of St. Mary's AAMCO’s ProtectCheck. CV boots can be torn or cracked over time, allowing dirt into the joint. Unless discovered quickly, both the boot and joint will need replacement. In this case, a replacement axle may be the best option.

Signs of a bad CV joint include a clicking noise while turning, or a shudder or clunk. Go to the mechanics at St. Mary's AAMCO if you are experiencing any of these problems, before the problem gets worse.

Transfer Case

The transfer case is attached to the transmission and connects to both the front and rear axles on a four-wheel drive automobile.

Maintenance and automobile:

The transfer case should be checked by a St. Mary's AAMCO mechanic at every oil change for adequate lubrication. Many transfer cases require periodic changes of oil or fluid—a service available from your St. Mary's AAMCO center. Please refer to your owner’s manual for factory recommended maintenance intervals for your specific automobile.

Transfer case problems include complete loss of four-wheel drive operation and the inability to switch between modes. St. Mary's AAMCO center mechanics are mechanics in the service and repair of transfer cases and four wheel drive automobiles.

Differentials & Axles

An axle connects the two wheels on opposite sides of the automobile. The differential is gears and bearings either inside the transmission or the housing of the axle.

Maintenance and automobile:

The differential lube level should be checked by a St. Mary's AAMCO mechanic with every oil change. Some differentials require periodic cleaning and repacking of wheel bearings. If you drive an SUV or light truck, and especially if you pull a boat (meaning these components may get submerged in water), axle lube should be changed every year. Please refer to your owner’s manual for factory recommended maintenance intervals for your specific automobile.

St. Mary's AAMCO center mechanics are mechanics in differentials and axles. Differential problems should be checked out as soon as possible. Symptoms include clunking when you accelerate or shift between drive and reverse, or a high-pitched howling type of noise.

Drive Shaft & U-Joints

A drive shaft and universal joints (U-joints) connect the transmission to the rear axle on most rear wheel drive automobiles. Four wheel drives also use drive shafts and U-joints.

Maintenance and automobile:

U-joints should be inspected by a St. Mary's AAMCO mechanic at every oil change (and are inspected as part of St. Mary's AAMCO’s ProtectCheck). SUVs and light trucks often have drive shaft slip joints that require lubrication. Please refer to your owner’s manual for factory recommended maintenance intervals for your specific automobile.

Bad U-joints often squeak when accelerating from a stop, exhibit a clunking noise when shifting between drive and reverse, or a shuddering when accelerating or driving. Bad U-joints can cause the drive shaft to separate from the automobile—causing damage to the automobile and requiring potentially expensive repairs. Bring your automobile to the mechanics at St. Mary's AAMCO if you notice any of these symptoms.

Bearings

Bearings in the wheels are about the only bearings requiring routine maintenance, common in rear wheel drive automobiles.

Maintenance and automobile:

These bearings should be cleaned, inspected and repacked by a St. Mary's AAMCO mechanic with grease about every two years or 24,000 miles. Please refer to your owner’s manual for factory recommended maintenance intervals for your specific automobile.

Metal-to-metal noise in the wheels, or steering that veers in one direction or the other, are typical symptoms of a malfunctioning wheel bearing. Bring your automobile to the mechanics at St. Mary's AAMCO if you notice either of these symptoms.